Racial/Ethnic Differences and Health Disparities Although there is much literature documenting racial differences in health, little is known about the underlying mechanisms linked to racial disparities in late life. Substantial literature suggests that body weight varies not only by race but also by socio economic status (SES), which is associated with accessibility to healthcare as well as with resource availability to maintain healthy life styles. Empirical literature also indicates that body weight is associated with chronic health conditions (CHC). However, literature has not adequately addressed underlying cross-sectional and longitudinal mechanisms involved in the relationships among race, body weight, and CHC in late life. The proposed study aims to examine to what extent racial disparities in the status of and changes in CHC are attributable to racial differences in the status of and changes in body mass index (BMI), controlling for SES. Using HRS (Health and Retirement Study) data from 1998, 2000, and 2002, which include combined samples and consistent designs/measurements between waves, this study has three specific aims. First, to examine risk factors associated with morbidity and comorbidity in eight diseases (e.g., hypertension, diabetes, cancer, lung disease, heart problems, stroke, arthritis, and incontinence), for which excessive body weight has been identified as a risk factor (U.S. Department of Health and Human Services, 2001). Specifically, using MIMIC models (multiple indicators, multiple causes), it will examine the relationships between the levels of BMI and morbidity and comorbidity of the eight CHC within each wave to test whether racial disparities in CHC are accounted for by racial differences in BMI. Second, using latent growth curve modeling, this study aims to examine risk factors of health trajectory with a focus on race and body weight, in order to examine whether racial disparities in the trajectories of CHC are explained by racial differences in baseline BMI. Third, using latent growth curve modeling, this study will estimate the causal relationship between BMI and CHC by examining the effects of initial BMI on the trajectories of CHC and the effects of initial CHC on the trajectory of BMI, as well as the relationships between the rate of change in BMI and the rates of change in CHC across the three time points. Using multi-group structural equation modeling, this study will further examine whether these causal relationships vary by race or by the levels of initial BMI.